Patent GB-653256-A (GB)
Title: Improvements in and relating to the coating of porous or absorbent materials
Inventor: HUDSON RONALD AUGUSTUS
IPC: B05D3/02
Filed: 1947-10-03
Abstract: Coating compositions for application to porous or absorbent materials or surfaces such as paper, cardboard, fabric, wood veneer, leather, and asbestos kegs, chemical tanks, ceilings, plaster walls, radio and other cabinets, and expanded, rigid, unplasticized polyvinyl chloride products, comprise a dispersion of a polymer or copolymer of a compound containing one CH2=C< group per molecule in a volatile partial solvent for the polymer.  The volatile solvent has a boiling point not appreciably exceeding 200 DEG  C., swells or partly dissolves the polymer when heated, and has a defined low rate of dissolving the polymer.  The polymer may be polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, or polythene.  Volatile partial solvents for polyvinyl chloride and polyvinylidene chloride are fatty acid esters, ketones, and polychloroaliphatic hydocarabons, e.g. the acetic esters of cyclohexanol, ethylene glycol monomethyl or monoethyl ether, and of aliphatic monohydric alcohols having 5 or 6 carbon atoms in their molecule, acetone, methyl ethyl ketone, trichlorethylene, and tetrachlorethane, cyclohexanone, and tetrahydronaphthalene.  The volatile partial solvent may be a mixture of liquids which may include solvents, plasticizers, and non-solvent diluents such as benzene, xylene, and alcohol.  Volatile partial solvents for polythene are benzene, toluene, xylene, tetrahydronaphthalene, trichlorethylene, carbon tetrachloride, and chlorobenzene.  Polythene dispersions may contain 2-50 per cent of a film-forming material capable of forming solid solutions with polythene, as described in Specification 613,018.  In examples: polyvinyl chloride is dispersed in (a) tetrahydronaphthalene and dioctyl phthalate; (b) tetrahydronaphthalene and cyclohexanone; (c) xylene, cyclohexanone, dioctyl phthalate, and a brown pigment ground with dioctyl phthalate.  In a further example a solution of polythene and polyisobutylene in xylene is formed by heating, poured into a mortar and ground while cooling to obtain a white powder, to which is added with further grinding a solution of polystyrene in xylene.  A paste-like dispersion is formed.  Specification 588,435 also is referred to.ALSO:Porous or absorbent materials or surfaces such as wood veneer, kegs, chemical tanks, ceilings, plaster walls, radio and other cabinets, and expanded, rigid, unplasticized polyvinyl chloride products, are coated by applying a layer of a dispersion of a polymer or copolymer of a compound containing one CH2=C< group per molecule in a volatile partial solvent for the polymer, pressing the layer against the material by means of a non-porous sheet material, heating the layer while so pressed to cause the dispersion to gel and to remove the volatile partial solvent, and subsequently stripping the non-porous sheet material from the coated surface.  The volatile solvent has a boiling point not appreciably exceeding 200 DEG  C. swells or partly dissolves the polymer when heated, and has a defined low rate of dissolving the polymer.  The polymer may be polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, or polythene. Volatile partial solvents for polyvinyl chloride and polyvinylidene chloride are fatty acid esters, ketones and polychloroaliphatic hydrocarbons, e.g. the acetic esters of cyclohexanol, ethylene glycol monomethyl or monoethyl ether, and of aliphatic monohydric alcohols having 5 or 6 carbon atoms in their molecule, acetone, methyl ethyl ketone, trichlorethylene, and tetrachlorethane, cyclohexanone and tetrahydronaphthalene.  The volatile partial solvent may be a mixture of liquids which may include solvents, plasticizers, and non-solvent diluents such as benzene, xylene, and alcohol.  Volatile partial solvents for polythene are benzene, toluene, xylene, tetrahydronaphthalene, trichlorethylene, carbon tetrachloride, and chlorobenzene.  Polythene dispersions may contain 2-50 per cent of a film-forming material capable of forming solid solutions with polythene, as described in Specification 613,018, [Group IV (a)]. The polymer layer may be applied in several spreading operations, heating between only sufficiently to avoid damage by handling.  The non-porous sheet may be of metal foil or regenerated cellulose and may have a smooth, engraved, or embossed surface.  The polymer layer may be heated to 100-200 DEG  C.  Low pressures such as 5 pounds per square inch may be applied, e.g. by laying a steel plate on top of the p  regenerated cellulose sheet, or by a domestic electric iron. Specification 588,435, [Group IV], also is referred to.